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authorZhang Yi <yi.zhang@huawei.com>2023-07-14 05:55:26 +0300
committerTheodore Ts'o <tytso@mit.edu>2023-08-04 23:32:05 +0300
commit373ac521799d9e97061515aca6ec6621789036bb (patch)
treec5d068cf9121b590f6520867b005c50085f9331c /fs/jbd2
parent4eea9fbed950f240bf6e627e1c784b8d54c54988 (diff)
downloadlinux-373ac521799d9e97061515aca6ec6621789036bb.tar.xz
jbd2: fix checkpoint cleanup performance regression
journal_clean_one_cp_list() has been merged into journal_shrink_one_cp_list(), but do chekpoint buffer cleanup from the committing process is just a best effort, it should stop scan once it meet a busy buffer, or else it will cause a lot of invalid buffer scan and checks. We catch a performance regression when doing fs_mark tests below. Test cmd: ./fs_mark -d scratch -s 1024 -n 10000 -t 1 -D 100 -N 100 Before merging checkpoint buffer cleanup: FSUse% Count Size Files/sec App Overhead 95 10000 1024 8304.9 49033 After merging checkpoint buffer cleanup: FSUse% Count Size Files/sec App Overhead 95 10000 1024 7649.0 50012 FSUse% Count Size Files/sec App Overhead 95 10000 1024 2107.1 50871 After merging checkpoint buffer cleanup, the total loop count in journal_shrink_one_cp_list() could be up to 6,261,600+ (50,000+ ~ 100,000+ in general), most of them are invalid. This patch fix it through passing 'shrink_type' into journal_shrink_one_cp_list() and add a new 'SHRINK_BUSY_STOP' to indicate it should stop once meet a busy buffer. After fix, the loop count descending back to 10,000+. After this fix: FSUse% Count Size Files/sec App Overhead 95 10000 1024 8558.4 49109 Cc: stable@kernel.org Fixes: b98dba273a0e ("jbd2: remove journal_clean_one_cp_list()") Signed-off-by: Zhang Yi <yi.zhang@huawei.com> Reviewed-by: Jan Kara <jack@suse.cz> Link: https://lore.kernel.org/r/20230714025528.564988-2-yi.zhang@huaweicloud.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Diffstat (limited to 'fs/jbd2')
-rw-r--r--fs/jbd2/checkpoint.c20
1 files changed, 14 insertions, 6 deletions
diff --git a/fs/jbd2/checkpoint.c b/fs/jbd2/checkpoint.c
index 9ec91017a7f3..936c6d758a65 100644
--- a/fs/jbd2/checkpoint.c
+++ b/fs/jbd2/checkpoint.c
@@ -349,6 +349,8 @@ int jbd2_cleanup_journal_tail(journal_t *journal)
/* Checkpoint list management */
+enum shrink_type {SHRINK_DESTROY, SHRINK_BUSY_STOP, SHRINK_BUSY_SKIP};
+
/*
* journal_shrink_one_cp_list
*
@@ -360,7 +362,8 @@ int jbd2_cleanup_journal_tail(journal_t *journal)
* Called with j_list_lock held.
*/
static unsigned long journal_shrink_one_cp_list(struct journal_head *jh,
- bool destroy, bool *released)
+ enum shrink_type type,
+ bool *released)
{
struct journal_head *last_jh;
struct journal_head *next_jh = jh;
@@ -376,12 +379,15 @@ static unsigned long journal_shrink_one_cp_list(struct journal_head *jh,
jh = next_jh;
next_jh = jh->b_cpnext;
- if (destroy) {
+ if (type == SHRINK_DESTROY) {
ret = __jbd2_journal_remove_checkpoint(jh);
} else {
ret = jbd2_journal_try_remove_checkpoint(jh);
- if (ret < 0)
- continue;
+ if (ret < 0) {
+ if (type == SHRINK_BUSY_SKIP)
+ continue;
+ break;
+ }
}
nr_freed++;
@@ -445,7 +451,7 @@ again:
tid = transaction->t_tid;
freed = journal_shrink_one_cp_list(transaction->t_checkpoint_list,
- false, &released);
+ SHRINK_BUSY_SKIP, &released);
nr_freed += freed;
(*nr_to_scan) -= min(*nr_to_scan, freed);
if (*nr_to_scan == 0)
@@ -485,19 +491,21 @@ out:
void __jbd2_journal_clean_checkpoint_list(journal_t *journal, bool destroy)
{
transaction_t *transaction, *last_transaction, *next_transaction;
+ enum shrink_type type;
bool released;
transaction = journal->j_checkpoint_transactions;
if (!transaction)
return;
+ type = destroy ? SHRINK_DESTROY : SHRINK_BUSY_STOP;
last_transaction = transaction->t_cpprev;
next_transaction = transaction;
do {
transaction = next_transaction;
next_transaction = transaction->t_cpnext;
journal_shrink_one_cp_list(transaction->t_checkpoint_list,
- destroy, &released);
+ type, &released);
/*
* This function only frees up some memory if possible so we
* dont have an obligation to finish processing. Bail out if